Magnetic capping layer structure for a spin torque oscillator

ABSTRACT

In one embodiment, a magnetic recording head includes: a main pole configured to generate a magnetic field for recording data on a magnetic recording medium; an oscillation device positioned above the main pole in a track direction, the oscillation device being configured to generate a high-frequency magnetic field; a magnetic capping layer positioned above the oscillation device in the track direction, the magnetic layer having a front region at a media facing side (MFS) of the magnetic recording head and a rear region positioned behind the front region in an element height direction, wherein a thickness of the front region of the magnetic capping layer is less than a thickness of the rear region thereof; and a trailing shield positioned above the magnetic capping layer in the track direction.

FIELD OF THE INVENTION

The present invention relates to data storage systems, and moreparticularly, this invention relates to a microwave assisted magneticrecording (MAMR) head including a magnetic capping layer structure for aspin torque oscillator present therein.

BACKGROUND

The heart of a computer is a magnetic hard disk drive (HDD) whichtypically includes a rotating magnetic disk, a slider that has read andwrite heads, a suspension arm above the rotating disk and an actuatorarm that swings the suspension arm to place the read and/or write headsover selected data tracks on the rotating disk. The suspension armbiases the slider into contact with the surface of the disk when thedisk is not rotating but, when the disk rotates, air is swirled by therotating disk adjacent an air bearing surface (ABS) of the slidercausing the slider to ride on an air bearing a slight distance from thesurface of the rotating disk. When the slider rides on the air bearingthe write and read heads are employed for writing magnetic impressionsto and reading magnetic signal fields from the rotating disk. The readand write heads are connected to processing circuitry that operatesaccording to a computer program to implement the writing and readingfunctions.

The volume of information processing in the information age isincreasing rapidly. In particular, it is desired that HDDs be able tostore more information in their limited area and volume. A technicalapproach to achieve this desire is to increase the capacity byincreasing the recording density of the HDD. To achieve higher recordingdensities, such as those exceeding 1 Tbit/inch², further miniaturizationof recording bits is effective, which in turn typically requires thedesign of smaller and smaller components.

The further miniaturization of the various components presents its ownset of challenges and obstacles. For instance, as the recording bit sizebecomes smaller, the loss of a recording state due to thermalfluctuation is of increasing concern. To compensate for thermalinstability associated with small recording bits, a magnetic recordingmedium with a large coercivity may be used. However, recording to amagnetic recording medium with a large coercivity requires a strongmagnetic field, which may exceed the amount of magnetic flux capable ofbeing generated by the magnetic recording head.

Microwave assisted magnetic recording (MAMR) has emerged as a promisingmagnetic recording technique to address the difficulty in maintainingboth the thermal stability and write-ability of a magnetic recordingmedium. In MAMR, an oscillation element or device is located next to ornear the write element in order to produce a high-frequency oscillatingmagnetic field (in addition to a recording magnetic field emanated froma main pole of the write element), which reduces an effective coercivityof a magnetic recording medium used to store data.

To further achieve higher recording densities using a MAMR head, therecording magnetic field and/or the high-frequency magnetic fieldgenerated by the main pole and oscillation device, respectively, may beincreased. Unfortunately, configuring the structural characteristicsand/or properties of the main pole and elements associated therewith toincrease the recording magnetic field may be constrained by thestructural characteristics and/or properties of the oscillation device,and vice versa. For instance, one method of increasing the recordingmagnetic field may involve narrowing the trailing gap positioned betweenthe main pole and the trailing shield of a MAMR head. However, theexistence of the oscillation device within the trailing gap rendersnarrowing the trailing gap to a thickness equivalent to or less than thethickness of the oscillation device problematic or impossible.

There are additional challenges associated with forming and using a MAMRhead. For example, formation of the stripe height of the oscillationdevice may generally involve an etching (e.g., milling) and/or cleaningprocess that results in a non-uniform thickness of the trailing gap andthus a non-uniform thickness in the oscillation device located within.

SUMMARY

According to one embodiment, a magnetic recording head includes: a mainpole configured to generate a magnetic field for recording data on amagnetic recording medium; an oscillation device positioned above themain pole in a track direction, the oscillation device being configuredto generate a high-frequency magnetic field; a magnetic capping layerpositioned above the oscillation device in the track direction, themagnetic layer having a front region at a media facing side (MFS) of themagnetic recording head and a rear region positioned behind the frontregion in an element height direction, wherein a thickness of the frontregion of the magnetic capping layer is less than a thickness of therear region thereof; and a trailing shield positioned above the magneticcapping layer in the track direction.

According to another embodiment, a method for forming a magneticrecording head includes: forming a main pole configured to generate amagnetic field for recording data on a magnetic recording medium;forming an oscillation device above the main pole in a track direction;forming a magnetic capping layer above the oscillation device in thetrack direction, wherein the magnetic layer is configured to preserve athickness of the oscillation device; defining a stripe height of theoscillation device and a stipe height of the magnetic capping layer;depositing an insulation layer behind the oscillation device and themagnetic capping layer in an element height direction; and cleaning anupper surface of the magnetic capping layer and an upper surface of theinsulation layer. After the cleaning, a thickness of a front region ofthe magnetic capping layer is less than a thickness of a rear regionthereof, the front region being positioned at a media facing side (MFS)of the magnetic recording head and the rear region being positionedbehind the front region in the element height direction.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a disk drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., hard disk) over themagnetic head, and a controller electrically coupled to the magnetichead.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings.

FIG. 1 is a simplified drawing of a magnetic recording disk drivesystem, according to one embodiment.

FIG. 2A is a cross-sectional view of a perpendicular magnetic head withhelical coils, according to one embodiment.

FIG. 2B is a cross-sectional view a piggyback magnetic head with helicalcoils, according to one embodiment.

FIG. 3A is a cross-sectional view of a perpendicular magnetic head withlooped coils, according to one embodiment.

FIG. 3B is a cross-sectional view of a piggyback magnetic head withlooped coils, according to one embodiment.

FIG. 4 is a schematic representation of a perpendicular recordingmedium, according to one embodiment.

FIG. 5A is a schematic representation of a recording head and theperpendicular recording medium of FIG. 4, according to one embodiment.

FIG. 5B is a schematic representation of a recording apparatusconfigured to record separately on both sides of a perpendicularrecording medium, according to one embodiment.

FIG. 6A is a media facing side (MFS) view of a schematic representationof a microwave assisted magnetic recording (MAMR) head, according to oneembodiment.

FIG. 6B is a cross-sectional view of the MAMR head of FIG. 6A.

FIG. 6C is cross-sectional view of a schematic representation of a MAMRhead, according to another embodiment.

FIGS. 7A-7L provide views of a MAMR head in various intermediate stagesof manufacture, illustrating a method for manufacturing a MAMR head,according to one embodiment.

FIGS. 8A-8G provide views of a conventional MAMR head in variousintermediate stages of manufacture, illustrating a prior art method formanufacturing a conventional MAMR head.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofdisk-based storage systems and/or related systems and methods, as wellas operation and/or component parts thereof.

In one general embodiment, a magnetic recording head includes: a mainpole configured to generate a magnetic field for recording data on amagnetic recording medium; an oscillation device positioned above themain pole in a track direction, the oscillation device being configuredto generate a high-frequency magnetic field; a magnetic capping layerpositioned above the oscillation device in the track direction, themagnetic layer having a front region at a media facing side (MFS) of themagnetic recording head and a rear region positioned behind the frontregion in an element height direction, wherein a thickness of the frontregion of the magnetic capping layer is less than a thickness of therear region thereof; and a trailing shield positioned above the magneticcapping layer in the track direction.

In another general embodiment, a method for forming a magnetic recordinghead includes: forming a main pole configured to generate a magneticfield for recording data on a magnetic recording medium; forming anoscillation device above the main pole in a track direction; forming amagnetic capping layer above the oscillation device in the trackdirection, wherein the magnetic layer is configured to preserve athickness of the oscillation device; defining a stripe height of theoscillation device and a stipe height of the magnetic capping layer;depositing an insulation layer behind the oscillation device and themagnetic capping layer in an element height direction; and cleaning anupper surface of the magnetic capping layer and an upper surface of theinsulation layer. After the cleaning, a thickness of a front region ofthe magnetic capping layer is less than a thickness of a rear regionthereof, the front region being positioned at a media facing side (MFS)of the magnetic recording head and the rear region being positionedbehind the front region in the element height direction.

Referring now to FIG. 1, there is shown a disk drive 100 in accordancewith one embodiment of the present invention. As shown in FIG. 1, atleast one rotatable magnetic medium (e.g., magnetic disk) 112 issupported on a spindle 114 and rotated by a drive mechanism, which mayinclude a disk drive motor 118. The magnetic recording on each disk istypically in the form of an annular pattern of concentric data tracks(not shown) on the disk 112. Thus, the disk drive motor 118 preferablypasses the magnetic disk 112 over the magnetic read/write portions 121,described immediately below.

At least one slider 113 is positioned near the disk 112, each slider 113supporting one or more magnetic read/write portions 121, e.g., of amagnetic head according to any of the approaches described and/orsuggested herein. As the disk rotates, slider 113 is moved radially inand out over disk surface 122 so that portions 121 may access differenttracks of the disk where desired data are recorded and/or to be written.Each slider 113 is attached to an actuator arm 119 by means of asuspension 115. The suspension 115 provides a slight spring force whichbiases slider 113 against the disk surface 122. Each actuator arm 119 isattached to an actuator 127. The actuator 127 as shown in FIG. 1 may bea voice coil motor (VCM). The VCM comprises a coil movable within afixed magnetic field, the direction and speed of the coil movementsbeing controlled by the motor current signals supplied by controller129.

During operation of the disk storage system, the rotation of disk 112generates an air bearing between slider 113 and disk surface 122 whichexerts an upward force or lift on the slider. The air bearing thuscounter-balances the slight spring force of suspension 115 and supportsslider 113 off and slightly above the disk surface by a small,substantially constant spacing during normal operation. Note that insome embodiments, the slider 113 may slide along the disk surface 122.

The various components of the disk storage system are controlled inoperation by control signals generated by controller 129, such as accesscontrol signals and internal clock signals. Typically, control unit 129comprises logic control circuits, storage (e.g., memory), and amicroprocessor. In a preferred approach, the control unit 129 iselectrically coupled (e.g., via wire, cable, line, etc.) to the one ormore magnetic read/write portions 121, for controlling operationthereof. The control unit 129 generates control signals to controlvarious system operations such as drive motor control signals on line123 and head position and seek control signals on line 128. The controlsignals on line 128 provide the desired current profiles to optimallymove and position slider 113 to the desired data track on disk 112. Readand write signals are communicated to and from read/write portions 121by way of recording channel 125.

The above description of a magnetic disk storage system, and theaccompanying illustration of FIG. 1 is for representation purposes only.It should be apparent that disk storage systems may contain a largenumber of disks and actuators, and each actuator may support a number ofsliders.

An interface may also be provided for communication between the diskdrive and a host (integral or external) to send and receive the data andfor controlling the operation of the disk drive and communicating thestatus of the disk drive to the host, all as will be understood by thoseof skill in the art.

Regarding a magnetic head, an inductive write portion therein includes acoil layer embedded in one or more insulation layers (insulation stack),the insulation stack being located between first and second pole piecelayers. A gap may be formed between the first and second pole piecelayers by a gap layer at an air bearing surface (ABS) of the writeportion. The pole piece layers may be connected at a back gap. Currentsare conducted through the coil layer, which produce magnetic fields inthe pole pieces. The magnetic fields fringe across the gap at the ABSfor the purpose of writing bits of magnetic field information in trackson moving media, such as in tracks on a rotating magnetic disk.

The second pole piece layer has a pole tip portion which extends fromthe ABS to a flare point and a yoke portion which extends from the flarepoint to the back gap. The flare point is where the second pole piecebegins to widen (flare) to form the yoke. The placement of the flarepoint directly affects the magnitude of the magnetic field produced towrite information on the recording medium.

FIG. 2A is a cross-sectional view of a perpendicular magnetic head 200,according to one embodiment. In FIG. 2A, helical coils 210 and 212 areused to create magnetic flux in the stitch pole 208, which then deliversthat flux to the main pole 206. Coils 210 indicate coils extending outfrom the page, while coils 212 indicate coils extending into the page.Stitch pole 208 may be recessed from the ABS 218. Insulation 216surrounds the coils and may provide support for some of the elements.The direction of the media travel, as indicated by the arrow to theright of the structure, moves the media past the lower return pole 214first, then past the stitch pole 208, main pole 206, trailing shield 204which may be connected to the wrap around shield (not shown), andfinally past the upper return pole 202. Each of these components mayhave a portion in contact with the ABS 218. The ABS 218 is indicatedacross the right side of the structure.

Perpendicular writing is achieved by forcing flux through the stitchpole 208 into the main pole 206 and then to the surface of the diskpositioned towards the ABS 218.

FIG. 2B illustrates one embodiment of a piggyback magnetic head 201having similar features to the head 200 of FIG. 2A. As shown in FIG. 2B,two shields 204, 214 flank the stitch pole 208 and main pole 206. Alsosensor shields 222, 224 are shown. The sensor 226 is typicallypositioned between the sensor shields 222, 224.

FIG. 3A is a schematic diagram of another embodiment of a perpendicularmagnetic head 300, which uses looped coils 310 to provide flux to thestitch pole 308, a configuration that is sometimes referred to as apancake configuration. The stitch pole 308 provides the flux to the mainpole 306. With this arrangement, the lower return pole may be optional.Insulation 316 surrounds the coils 310, and may provide support for thestitch pole 308 and main pole 306. The stitch pole may be recessed fromthe ABS 318. The direction of the media travel, as indicated by thearrow to the right of the structure, moves the media past the stitchpole 308, main pole 306, trailing shield 304 which may be connected tothe wrap around shield (not shown), and finally past the upper returnpole 302 (all of which may or may not have a portion in contact with theABS 318). The ABS 318 is indicated across the right side of thestructure. The trailing shield 304 may be in contact with the main pole306 in some embodiments.

FIG. 3B illustrates another embodiment of a piggyback magnetic head 301having similar features to the head 300 of FIG. 3A. As shown in FIG. 3B,the piggyback magnetic head 301 also includes a looped coil 310, whichwraps around to form a pancake coil. Sensor shields 322, 324 areadditionally shown. The sensor 326 is typically positioned between thesensor shields 322, 324.

In FIGS. 2B and 3B, an optional heater is shown near the non-ABS side ofthe magnetic head. A heater (Heater) may also be included in themagnetic heads shown in FIGS. 2A and 3A. The position of this heater mayvary based on design parameters such as where the protrusion is desired,coefficients of thermal expansion of the surrounding layers, etc.

FIG. 4 provides a schematic diagram of a simplified perpendicularrecording medium 400, which may also be used with magnetic diskrecording systems, such as that shown in FIG. 1. As shown in FIG. 4, theperpendicular recording medium 400, which may be a recording disk invarious approaches, comprises at least a supporting substrate 402 of asuitable non-magnetic material (e.g., glass, aluminum, etc.), and a softmagnetic underlayer 404 of a material having a high magneticpermeability positioned above the substrate 402. The perpendicularrecording medium 400 also includes a magnetic recording layer 406positioned above the soft magnetic underlayer 404, where the magneticrecording layer 406 preferably has a high coercivity relative to thesoft magnetic underlayer 404. There may one or more additional layers(not shown), such as an “exchange-break” layer or “interlayer”, betweenthe soft magnetic underlayer 404 and the magnetic recording layer 406.

The orientation of magnetic impulses in the magnetic recording layer 406is substantially perpendicular to the surface of the recording layer.The magnetization of the soft magnetic underlayer 404 is oriented in (orparallel to) the plane of the soft underlayer 404. As particularly shownin FIG. 4, the in-plane magnetization of the soft magnetic underlayer404 may be represented by an arrow extending into the paper.

FIG. 5A illustrates the operative relationship between a perpendicularhead 508 and the perpendicular recording medium 400 of FIG. 4. As shownin FIG. 5A, the magnetic flux 510, which extends between the main pole512 and return pole 514 of the perpendicular head 508, loops into andout of the magnetic recording layer 406 and soft magnetic underlayer404. The soft magnetic underlayer 404 helps focus the magnetic flux 510from the perpendicular head 508 into the magnetic recording layer 406 ina direction generally perpendicular to the surface of the magneticmedium. Accordingly, the intense magnetic field generated between theperpendicular head 508 and the soft magnetic underlayer 404, enablesinformation to be recorded in the magnetic recording layer 406. Themagnetic flux is further channeled by the soft magnetic underlayer 404back to the return pole 514 of the head 508.

As noted above, the magnetization of the soft magnetic underlayer 404 isoriented in (parallel to) the plane of the soft magnetic underlayer 404,and may represented by an arrow extending into the paper. However, asshown in FIG. 5A, this in plane magnetization of the soft magneticunderlayer 404 may rotate in regions that are exposed to the magneticflux 510.

FIG. 5B illustrates one embodiment of the structure shown in FIG. 5A,where soft magnetic underlayers 404 and magnetic recording layers 406are positioned on opposite sides of the substrate 402, along withsuitable recording heads 508 positioned adjacent the outer surface ofthe magnetic recording layers 406, thereby allowing recording on eachside of the medium.

Except as otherwise described herein with reference to the variousinventive embodiments, the various components of the structures of FIGS.1-5B, and of other embodiments disclosed herein, may be of conventionalmaterial(s), design, and/or fabricated using conventional techniques, aswould become apparent to one skilled in the art upon reading the presentdisclosure.

Referring now to FIG. 6A, a media facing side (MFS) view of a simplifiedMAMR head 600 is shown according to one embodiment. As an option, theMAMR head 600 may be implemented in conjunction with features from anyother embodiment listed herein, such as those described with referenceto the other FIGS. Of course, the MAMR head 600 and others presentedherein may be used in various applications and/or in permutations whichmay or may not be specifically described in the illustrative embodimentslisted herein. For instance, the MAMR head 600 may include more or lesscomponents than those shown in FIG. 6A, in various approaches. Moreover,unless otherwise specified, one or more components of the MAMR head 600may be of conventional material(s), design, and/or fabricated usingconventional techniques (e.g., sputtering, plating, atomic layerdeposition (ALD), chemical vapor deposition (CVD), ion milling, etc.),as would become apparent to one skilled in the art upon reading thepresent disclosure.

As particularly shown in FIG. 6A, the MAMR head 600 includes a main pole602 configured to generate a recording magnetic field when current isapplied to a write coil. The main pole 602 includes an upper surface604, and first and second side surfaces 606, 608.

In various approaches, the main pole 602 may have a generally triangularshape as shown. Accordingly, the first and second side surfaces 606, 608may be angled at a first angle of inclination, θ₁, relative to a planeof deposition of the MAMR head 600 (i.e., the x-y plane in FIG. 6A). Inpreferred approaches, the first angle of inclination, θ₁, may be in arange from greater than 0° to less than or equal to 90°. It is importantto note, however, that the main pole 602 is not limited to a triangularshape, and may include a trapezoidal shape in some approaches, or othersuch suitable shapes as would become apparent to one having skill in theart upon reading the present disclosure.

In additional approaches, the main pole 602 may include one or moremagnetic metals, such as Fe, Co, Ni, alloys thereof, etc.

A side gap 610 may be present on either side of the main pole 602 in thecross track direction. In preferred approaches, the side gap 610 maycomprise a non-magnetic material such as alumina, TiO₂, SiO₂,Al₂O₃—SiO₂, etc.

A magnetic side shield 612 may be present on either side of the side gap610 in the cross track direction. The magnetic side shield 612 maycomprise one or more magnetic materials, including but not limited toNi, Fe, Co, alloys thereof, etc.

As also shown in FIG. 6A, an oscillation device 614 is positioned abovea portion of the main pole 602 in the track direction (i.e., thedirection in which a magnetic recording medium advances). Theoscillation device includes an upper surface 616 and first and secondside surfaces, 618, 620.

The first and second side surfaces 618, 620 of the oscillation device614 may be angled at a second angle of inclination, θ₂, relative to theplane of deposition of the MAMR head 600. As shown in the embodiment ofFIG. 6A, the second angle of inclination, θ₂, may be about 90° relativeto the plane of deposition of the MAMR head 600. However, in otherapproaches, the second angle of inclination, θ₂, may be in a range thatis greater than 0° and less than or equal to about 90° relative to theplane of deposition of the MAMR head 600. In yet more approaches, thesecond angle of inclination, θ₂, may be about equal to the first angleof inclination, θ₁.

In some approaches, the width, w_((osc)), of the oscillation device 614in the cross track direction may be less than a width, w_((mp)), of theupper surface 604 of the main pole, as shown. In more approaches, thewidth w_((osc)) may be about equal to than the width w_((mp)).

In particular approaches, the thickness, t_((osc)), of the oscillationdevice 614 may be uniform in the cross track direction. In moreapproaches, the thickness, t_((osc)), of the oscillation device maydefine the thickness of the trailing gap (TG).

In some approaches, the oscillation device 614 may be a spin torqueoscillator (STO), as shown in the embodiment of FIG. 6A. The oscillationdevice 614 may thus include an underlayer 622 configured to promote adesired grain growth and magnetization in the layers formed thereabove.In various approaches, the underlayer 622 may include one or more layersthat comprise at least one of Cu, Ag, Au, Cr, Pt, Ti, Zr, Hf, V, Nb, Ta,Ru, Os, Pd, Pt, Rh, Ir, alloys thereof, etc. In one particular approach,the underlayer 622 may comprise a first layer including Cu, and a secondlayer positioned thereabove in the track direction including Ta.

The oscillation device 614 may also include a spin polarization layer624 positioned above the underlayer 622 in the track direction. Inpreferred approaches, the spin polarization layer (SPL) 624 may have amagnetic anisotropy oriented perpendicular to the plane of deposition ofthe MAMR head 600. The SPL 624 may be chosen such that when an electriccurrent flows to the oscillation device 614, the electron spin producedby the SPL 624 has the same orientation thereof. These electrons imparta torque (“spin torque”) to the magnetization of the high-frequencymagnetic field generation layer (FGL) 628 and, as a result, amagnetization rotation of the FGL 628 occurs. This magnetizationrotation of the FGL 628 forms the high-frequency magnetic field emittedby the oscillation device 614. In various approaches, the SPL 624 mayinclude at least one of CoPt, CoNi, CoPd, CoCrTaPd, or other suitablemagnetic material as would become apparent to one having skill in theart upon reading the present disclosure.

The oscillation device 614 further includes an intermediate layer 626positioned between the SPL 624 and the FGL 628 in the track direction.In some approaches, the intermediate layer 626 may include one or morenon-magnetic materials, including but not limited to, Au, Ag, Pt, Ta,Ir, Al, Si, Ge, Ti, Cu, Pd, Ru, Mo, W, alloys thereof, etc.

In more approaches, the FGL 628 may include one or more magneticmaterials, including but not limited to FeCo, NiFe, CoPt, CoCr, CoIr,CoFeAli, CoFeGe, CoMnGe, CoFeAl, CoFeSi, CoMnSi, TbFeCo, etc.

The oscillation device 614 additionally includes a non-magnetic cappinglayer 630 positioned above the FGL 628. In various approaches, thenon-magnetic capping layer 630 may include one or more layers thatcomprise at least one of NiCr, NiFe, Cr, Pt, Ir, Ta, Ru, alloys thereof,etc. In one particular approach, the non-magnetic capping layer 630 maycomprise: a first layer including NiCr; a second layer positioned abovethe first layer in the track direction, the second layer including Ir; athird layer positioned above the second layer in the track direction,the third layer including Ta; and a fourth layer positioned above thethird layer in the track direction, the fourth layer including Ru.

As also shown in FIG. 6A, a magnetic capping layer 632 is positionedabove the oscillation device 614 in the track direction. The magneticcapping layer 632 includes an upper surface 634 and first and secondside surfaces 636, 638. The first and second side surfaces 636, 638 ofthe magnetic capping layer 632 may be angled at a third angle ofinclination, θ₃, relative to the plane of deposition of the MAMR head600. As shown in the embodiment of FIG. 6A, the third angle ofinclination, θ₃, may be about 90° relative to the plane of deposition ofthe MAMR head 600. However, in other approaches, the third angle ofinclination, θ₃, may be in a range that is greater than 0° and less thanor equal to about 90° relative to the plane of deposition of the MAMRhead 600. In yet more approaches, the third angle of inclination, θ₃,may be about equal to the second angle of inclination, θ₂.

The width, w_(mc), of the magnetic capping layer 632 may be about equalto the width, w_((osc)), of the oscillation device 614 in variousapproaches. Moreover, the magnetic capping layer 632 may be configuredto preserve the thickness of oscillation device 614.

In various approaches, the magnetic capping layer 632 may include one ormore magnetic materials, including, but not limited to, Fe, Co, Ni,alloys thereof, etc.

A track width (TW) insulation layer 640 may be positioned on either sideof the oscillation device 614 and the magnetic capping layer 632 in thecross track direction. The TW insulation layer 640 may comprise anon-magnetic material such as alumina, TiO₂, SiO₂, Al₂O₃—SiO₂, etc. Insome approaches, the thickness, in the track direction, of the portionof the TW insulation layer 640 present at the MFS of the MAMR head 600may be about equal to or greater than a combined thickness of theoscillation device 614 and the magnetic capping layer 632 at the MFS.

As further shown in FIG. 6A, a trailing shield 642 is positioned abovethe magnetic capping layer 632 and the TW insulation layer 640. Thetrailing shield 642 may include one or more magnetic materials, such asFe, Co, Ni, alloys thereof, etc., in various approaches. In someapproaches, the trailing shield 642 and the magnetic capping layer 632may be magnetically coupled. In one particular approach, the trailingshield 642 and the magnetic capping layer 632 may include at least onemagnetic material in common.

While not shown in FIG. 6A, a trailing shield seed layer may bepositioned between at least the magnetic capping layer 632 and thetrailing shield 642. In some approaches, the trailing shield seed layermay include an electrically conductive material, and have a highmagnetic saturation moment so as to function as a part of the trailingshield 642. Alternatively, the trailing shield seed layer may be anelectrically conductive non-magnetic material (e.g., Ru, Rh, etc.) so asto function as a gap layer and an electroplating seed layer.

Referring now to FIG. 6B, a cross-sectional view of the MAMR head 600described above in FIG. 6A is shown according to one embodiment. Asshown in FIG. 6B, the main pole 602 includes a tapered region 644 havinga tapered upper surface on an end near the MFS 646.

As also shown in FIG. 6B, the oscillation device 614 is located on thetapered region 644 of the main pole 602. The oscillation device also hasa front edge 648 located at the MFS 646 and a back edge 650 positionedtherebehind in the element height direction. The distance between thefront and back edges 648, 650 of the oscillation device 614 in theelement height direction is referred to as the stripe height of theoscillation device 614. In preferred approaches, the thickness of theoscillation device 614 may be uniform in the element height direction.In more preferred approaches, the thickness of the oscillation devicemay be uniform in both the cross track and element height directions.

As also shown in FIG. 6B, the magnetic capping layer 632 has a frontedge 652 located at the MFS 646 and a back edge 654 positionedtherebehind in the element height direction. The magnetic capping layer632 also includes a front region 656 located at or near the front edge652, and a rear region 658 located at or near the back edge 654.

In particular approaches, the thickness of the magnetic capping layer632 may be about uniform in the cross track direction, but may increasefrom the front edge 652 to the back edge 654 in the element heightdirection. For instance, in preferred approaches, the thickness,t_(1(mc)), of the front region 656 of the magnetic capping layer 632 maybe less than the thickness, t_(2(mc)), of the rear region 658 of themagnetic capping layer 632. In some approaches, the thickness oft_(1(mc)) may be in a range from about 4 nm to less than about 25 nm,and the thickness of t_(2(mc)) be in a range from greater than about 4nm to about 25 nm. In one particular approach, the thickness t_(1(mc))may be in a range from about 4 nm to about 8 nm, whereas the thicknesst_(2(mc)) may be in a range from about 9 nm to about 25 nm.

The lower surface 660 of the magnetic capping layer 632 may lie alongsubstantially the same plane, where said plane is angled at a fourthangle of inclination, θ₄, relative to the plane of deposition of theMAMR head 600, as shown in the embodiment of FIG. 6B. The fourth angleof inclination, θ₄, may preferably be in a range from greater than 0° toless than 90° relative to the plane of deposition of the MAMR head 600.

The upper surface 634 of the magnetic capping layer 632 may lie alongsubstantially the same plane, where said plane is angled at a fifthangle of inclination, θ₅, relative to the plane of deposition of theMAMR head 600, as shown in the embodiment of FIG. 6B. The fifth angle ofinclination, θ₅, may preferably be in a range from greater than 0° toless than 90° relative to the plane of deposition of the MAMR head 600.Moreover, in particular approaches, the fifth angle of inclination, θ₅,may be greater than the fourth angle of inclination, θ₄, a configurationwhich results in the thickness, t_(1(mc)), of the front region 656 ofthe magnetic capping layer 632 being less than the thickness, t_(2(mc)),of the rear region 658 thereof.

As further shown in FIG. 6B, a stripe height (SH) insulation layer 662is positioned behind the back edges 650, 654 of the oscillation device614 and the magnetic capping layer 632, respectively. The SH insulationlayer 662 may comprise a non-magnetic material such as alumina, TiO₂,SiO₂, Al₂O₃—SiO₂, etc. In some approaches, SH insulation layer 662 maycomprise one or more of the same non-magnetic materials as the TWinsulation layer 640 (not shown in the cross-sectional view provided inFIG. 6B); however, in other approaches, the SH and TW insulation layers662, 640 may comprise different non-magnetic materials.

The SH insulation layer 662 may include a forward region 664 having anupper surface 668 on an end near the back edges 650, 654 of theoscillation device 614 and the magnetic capping layer 632, respectively.

The thickness of the forward region 664 of the SH insulation layer 662may increase toward a back edge of the forward region 664 in the elementheight direction relative to the MFS 646.

In some approaches, at least a portion of the upper surface 668 of theforward region 664 of the SH insulation layer 662 may be angled at asixth angle of inclination, θ₆, relative to the plane of deposition ofthe MAMR head 600. Preferably, the sixth angle of inclination, θ₆, maybe in a range from greater than 0° to less than 90° relative to theplane of deposition of the MAMR head 600. In some approaches, the sixthangle of inclination, θ₆, may be about equal to or greater than thefifth angle of inclination, θ₅.

In more approaches, at least a portion of the upper surface 668 of theforward region 664 of SH insulation layer 662 may lie in substantiallythe same plane as a portion of the upper surface 634 of the magneticcapping layer 632.

As also shown in FIG. 6B, a non-magnetic bump layer 670 may be includedbetween the main pole 602 and the SH insulation layer 640. In someapproaches, the non-magnetic bump layer may be a continuation of the SHinsulation layer 662 material. In other approaches, the non-magneticbump layer 670 and the SH insulation layer 662 may include differentnon-magnetic materials.

As discussed previously, the upper surface 634 of the magnetic cappinglayer 632 may lie in substantially the same plane angled at the thirdangled of inclination, θ₃, relative to the plane of deposition of theMAMR head 600. It is important to note, however, that in alternativeapproaches, one or more portions of the upper surface 634 of themagnetic capping layer 632 may be angled at different angles ofinclination relative to the plane of deposition of the MAMR head 600,provided again that the thickness, t_(1(mc)), is less than thethickness, t_(2(mc)). For example, at least two portions of the uppersurface 634 of the magnetic capping layer 632 may be angled at differentangles of inclination relative to the plane of deposition of the MAMRhead 600; at least three portions of the upper surface 634 of themagnetic capping layer 632 may be angled at different angles ofinclination relative to the plane of deposition of the MAMR head 600;etc.

FIG. 6C, illustrates one non-limiting embodiment of a MAMR head 601 inwhich two portions of the upper surface 634 of the magnetic cappinglayer 632 are angled at different angles of inclination relative to theplane of deposition of the MAMR head 600. As the MAMR head 601 of FIG.6B is a variation of the MAMR head 600 of FIGS. 6A-6B, features of theMAMR head 601 of FIG. 6B may have common numbering with those of theMAMR head 600 embodied in FIGS. 6A-6B.

As particularly shown in FIG. 6C, the front region 656 and the rearregion 658 of the magnetic capping layer 632 are angled at a seventhangle of inclination, θ₇, and an eighth angle of inclination, θ₈,respectively, relative to the plane of deposition of the MAMR head 600.The angles θ₇ and θ₈ may each independently be in a range from greaterthan 0° to less than 90° relative to the plane of deposition of the MAMRhead 600, with the proviso that θ₈>θ₇, as shown in the embodiment ofFIG. 6C. The angle θ₇ may also be about equal to or greater than θ₄, andthe angle θ₈ may be greater than θ₄, in some approaches.

As additionally shown in FIG. 6C, at least a portion of the uppersurface 668 of the forward region 664 of the SH insulation layer 662 maybe angled at the sixth angle of inclination, θ₆, relative to the planeof deposition of the MAMR head 600. In some approaches, the sixth angleof inclination, θ₆, may be about equal to or greater than the seventhangle of inclination, θ₇, or the eighth angle of inclination, θ₈. Inmore approaches, at least a portion of the upper surface 668 of theforward region 664 of the SH insulation layer 662 may lie insubstantially the same plane as at least a portion of the upper surface634 of the magnetic capping layer 632.

Referring now to FIGS. 7A-7L, a method in process flow by which a MAMRhead may be formed, is shown according to one embodiment. As an option,the present method may be implemented to construct structures such asthose shown in the other figures. Of course, the present method andothers presented herein may be used to form magnetic structures for awide variety of devices and/or purposes which may or may not be relatedto magnetic recording. It should be noted that any aforementionedfeatures may be used in any of the embodiments described in accordancewith the various methods. It should also be noted that the presentmethod may include more or less steps than those described and/orillustrated in FIGS. 7A-7L, according to various approaches. Moreover,unless otherwise specified, formation of one or more components of theMAMR head may include conventional techniques (e.g., sputtering,plating, atomic layer deposition (ALD), chemical vapor deposition (CVD),ion milling, etc.), as would become apparent to one skilled in the artupon reading the present disclosure. Further, the present method andothers presented herein may be carried out in any desired environment.

As shown in FIG. 7A, a main pole 702 is deposited above a substrate 704.In various approaches, the main pole 702 may include one or moremagnetic metals, such as Fe, Co, Ni, alloys thereof, etc.

As shown in FIG. 7B, a first mask 706 is formed above a portion of themain pole 702. The first mask 706 may include a layer ofphotolithographically patterned photoresist, in addition to other layerssuch as one or more hard mask layers, an image transfer layer, ananti-reflective coating etc. FIG. 7C provides a top down view as seenfrom line A-A of FIG. 7B.

As shown in FIG. 7D, portions of the main pole 702 not covered by thefirst mask 706 are removed by a first removal process. This firstremoval process may include ion milling, reactive ion etching (RIE),deep RIE, inductively coupled plasma RIE, or other such removal processas known in the art. In preferred approaches, this first removal processmay involve an ion milling process performed in a sweeping manner and atan angle relative to normal so that shadowing from the first mask 706may cause the ion milling to form the trailing edge tapered (TET)structure of the main pole 702. For instance, after the first removalprocess, the main pole 702 includes a tapered region 708 near theto-be-defined media facing side (MFS).

As shown in FIG. 7E, the first mask 706 is removed and an oscillationdevice 710 is deposited above the main pole 702. Given that the mainpole 702 has a TET structure, the oscillation device 710 depositedthereabove also includes a tapered region 712 near the to-be-definedMFS.

The oscillation device 710 may be a spin torque oscillator (STO) andcomprise a plurality of layers described below. However, it is importantto note that the oscillation device 710 is not limited to a STO, asvarious other oscillator designs may be used.

As shown in FIG. 7E, the oscillation device 710 includes the followinglayers in the recited order: an underlayer 714, a spin polarizationlayer (SPL) 716, an intermediate layer 718, a high-frequency magneticfield generation layer (FGL) 720, and a non-magnetic capping layer 722.

The underlayer 714 may be configured to promote a desired grain growthand magnetization in the layers formed thereabove. In variousapproaches, the underlayer 714 may include one or more layers thatcomprise at least one of Cu, Ag, Au, Cr, Ti, Zr, Hf, V, Nb, Ta, Ru, Os,Pd, Pt, Rh, Ir, alloys thereof, etc.

The SPL 716 may preferably have a magnetic anisotropy orientedperpendicular to the plane of deposition (defined by the x-y plane inFIG. 7A), and is configured to provide spin torque to the magnetizationof the FGL 720. In various approaches, the SPL 716 may include at leastone of CoPt, CoNi, CoPd, CoCrTaPd, or other suitable magnetic materialas would become apparent to one having skill in the art upon reading thepresent disclosure.

The intermediate layer 718 positioned between the SPL 716 and the FGL720 in the track direction may include one or more non-magneticmaterials, such as Au, Ag, Pt, Ta, Ir, Al, Si, Ge, Ti, Cu, Pd, Ru, Cr,Mo, W, alloys thereof, etc.

The FGL 720 may include one or more magnetic materials, including butnot limited to FeCo, NiFe, CoPt, CoCr, CoIr, CoFeAli, CoFeGe, CoMnGe,CoFeAl, CoFeSi, CoMnSi, TbFeCo, etc.

The non-magnetic capping layer 722 may include one or more layers thatcomprise at least one of NiCr, NiFe, Cr, Pt, Ir, Ta, Ru, alloys thereof,etc.

As shown in FIG. 7F, a magnetic capping layer 724 is deposited above theoscillation device 710. The magnetic capping layer 724 also includes atapered region 726. In various approaches, the magnetic capping layer724 may include one or more magnetic materials such as Fe, Co, Ni,alloys thereof, etc. In some approaches, the magnetic capping layer 724may have at least one magnetic material in common with ayet-to-be-formed trailing shield.

As shown in FIG. 7G, a second mask 728 is formed above at least aportion of the tapered region 726 of the magnetic capping layer 724. Thesecond mask 728 has a shape configured to define a stripe height of theoscillation device 710 and the magnetic capping layer 724 as measuredfrom the MFS. The second mask 728 may include a layer ofphotolithographically patterned photoresist, in addition to other layerssuch as one or more hard mask layers, an image transfer layer, ananti-reflective coating etc.

As shown in FIG. 7H, portions of the magnetic capping layer 724 and theoscillation device 710 not covered by the second mask 728 are removed bya second removal process. This second removal process may include ionmilling, reactive ion etching (RIE), deep RIE, inductively coupledplasma RIE, or other such removal process as known in the art. Afterthis second removal process, a back edge 730 of the magnetic cappinglayer 724 and a back edge 732 of the oscillation device 710 are defined.

As shown in FIG. 7I, a stripe height (SH) insulation layer 734 isdeposited above the second mask 728, as well as portions of thestructure left exposed after the aforementioned removal process. The SHinsulation layer 734 may comprise a non-magnetic material such asalumina, TiO₂, SiO₂, Al₂O₃—SiO₂, etc. In various approaches, the SHinsulation layer 734 may be sufficiently thick so as to enable formationof a non-magnetic, self-alignment bump (not shown).

As shown in FIG. 7J, the second mask 728 having the SH insulation layer734 thereon is removed via a chemical liftoff process, or other suchsuitable process known in the art. The surface from which the secondmask 728 is removed may then be subject to a cleaning process (e.g.,chemical mechanical polishing) resulting in the structure of FIG. 7K.

As particularly shown in FIG. 7K, the aforementioned cleaning processmay lead to the removal of one or more portions of the magnetic cappinglayer 724. Accordingly, after the cleaning process, the thickness of themagnetic capping layer 724 may increase from the MFS toward the backedge 730 thereof in the element height direction. Stated another way,the thickness, t_(1(mc)), of the region of the magnetic capping layer724 near the MFS may be less than the thickness, t_(2(mc)), of theregion of the magnetic capping layer 724 near the back edge 730 thereof.In some approaches, the thickness t_(1(mc)) may be in a range from about4 nm to less than about 25 nm, and the thickness t_(2(mc)) may be in arange from greater than about 4 nm to about 25 nm.

As also shown in FIG. 7K, the aforementioned cleaning process may leadto the removal of one or more portions of the SH insulation layer 734.The SH insulation layer 734 includes a forward region 736 near the backedges 730, 732 of the magnetic capping layer 724 and the oscillationdevice 710, respectively. The thickness of the forward region 736 of theSH insulation layer 734 may increase (preferably in a substantiallylinear fashion) toward the back edge 738 thereof in the element heightdirection relative to the MFS. In some approaches, one or more portionsof the upper surface 740 of the forward region 736 of the SH insulationlayer 734 may lie in substantially the same plane as one or moreportions of the upper surface 742 of the magnetic capping layer 724,where said plane is angled at an angle of inclination (preferablygreater than 0° and less than 90°) relative to the plane of depositionof the MAMR head.

It is of note that the presence of the magnetic capping layer 724 maymitigate and/or eliminate the masking effect of a thick SH insulationlayer 734 during process variations associated with the cleaningprocess. For instance, as noted above, after removal of the second mask728 and prior to the cleaning process, a thick SH insulation layer 734may be present behind the magnetic capping layer 724 and oscillationdevice 710 in the element height direction. This thick SH insulationlayer 734 may function effectively as a milling mask, thereby makingcleaning of the SH insulation layer 734 and the surrounding vicinitydifficult. Without the protection of the magnetic capping layer 724,there is a risk of over-cleaning the areas near the thick SH insulationlayer 734, areas which include the oscillation device 710. Accordingly,without the protection of the magnetic capping layer 724, the cleaningprocess may result in the oscillation device 710 having a non-uniformthickness in the element height direction, as seen in conventional MAMRheads that do not have the magnetic capping layer 724 but are otherwiseidentical to the novel MAMR heads described herein.

However, as evident in FIG. 7K, the magnetic capping layer 724 preservesthe total thickness of the oscillation device 710, which may also definethe trailing gap thickness, during the cleaning process and othersubsequent manufacturing steps. Accordingly, the oscillation device 710has a uniform thickness, t_((osc)), in the element height direction (asshown in FIG. 7K), and the cross track direction (not shown).

As shown in FIG. 7L, a trailing shield 744 is deposited above themagnetic capping and SH insulation layers 724, 734. The trailing shield744 may include one or more magnetic materials, such as Fe, Co, Ni,alloys thereof, etc., in various approaches. In some approaches, thetrailing shield 744 and the magnetic capping layer 724 may bemagnetically coupled. In one particular approach, the trailing shield744 and the magnetic capping layer 724 may include at least one magneticmaterial in common.

While not shown in FIG. 7L, a trailing shield seed layer may bepositioned between at least the magnetic capping layer 724 and thetrailing shield 744. In some approaches, the trailing shield seed layermay include an electrically conductive material, and have a highmagnetic saturation moment so as to function as a part of the trailingshield 744. Alternatively, the trailing shield seed layer may be anelectrically conductive non-magnetic material (e.g., Ru, Rh, etc.) so asto function as a gap layer and an electroplating seed layer.

It is also important to note that while not shown in FIGS. 7A-7L, themethod associated therewith may include additional steps, e.g., todefine the width of the oscillation device 710 in the cross trackdirection, to deposit a track width (TW) insulation layer on either sideof the oscillation device 710 and the magnetic capping layer 724 in thecross track direction, etc.

To better understand the benefits of the MAMR heads described above withreference to FIGS. 6A-6C, and the benefits of manufacturing a MAMR headaccording to a method such as that described above with reference toFIGS. 7A-7L, it is helpful to compare such MAMR heads and method with aprior art method of manufacturing a conventional MAMR head. FIGS. 8A-8Gillustrate a typical prior art method of manufacturing a conventionalMAMR head.

As shown in FIG. 8A, an oscillation device 802 is deposited above a mainpole 804 that has a tapered portion 806 near the to-be-defined mediafacing side (MFS). Given the trailing edge tapered (TET) structure ofthe main pole 804, the oscillation device 802 deposited thereabove alsoincludes a tapered region 808 near the to-be-defined MFS.

The oscillation device 802 may be a spin torque oscillator comprisingthe following layers in order: an underlayer 810, a spin polarizationlayer (SPL) 812, an intermediate layer 814, a high-frequency magneticfield generation layer (FGL) 816, and a non-magnetic capping layer 818.

As shown in FIG. 8B, a mask 820 is formed above at least a portion ofthe tapered region 808 of the oscillation device 802. The mask 820 has ashape configured to define a stripe height of the oscillation device 802as measured from the MFS. The mask 820 may include a layer ofphotolithographically patterned photoresist, in addition to other layerssuch as one or more hard mask layers, an image transfer layer, ananti-reflective coating etc.

As shown in FIG. 8C, portions of oscillation device 802 not covered bythe mask 820 are removed by a removal process. This removal process mayinclude ion milling, reactive ion etching (RIE), deep RIE, inductivelycoupled plasma RIE, or other such removal process as known in the art.After this removal process, a back edge 822 of the oscillation device802 is defined.

As shown in FIG. 8D, a stipe height (SH) insulation layer 824 isdeposited above the mask 820, as well as portions of the structure leftexposed after the aforementioned removal process. In various approaches,the SH insulation layer 824 may be sufficiently thick so as to enableformation of a non-magnetic, self-alignment bump (not shown).

As shown in FIG. 8E, the mask 820 having the SH insulation layer 824thereon is removed via a chemical liftoff process, or other suchsuitable process known in the art. The surface from which the mask 820is removed may then be subject to a cleaning process (e.g., chemicalmechanical polishing) resulting in the structure of FIG. 8F.

As particularly shown in FIG. 8F, the aforementioned cleaning processmay lead to the removal of one or more portions of the SH insulationlayer 824. Accordingly, after the cleaning process, the thickness of aforward region 826 of the SH insulation layer 824 may increase toward aback edge 828 thereof in the element height direction relative to theMFS.

As also shown in FIG. 8F, the aforementioned cleaning process may leadto the removal of one or more portions of the oscillation device 802.Accordingly, after the cleaning process, the thickness of theoscillation device 802 (and thus the thickness of the trailing gap) maynot be uniform in the element height direction, i.e., the thickness ofthe oscillation device 802 may increase from the MFS toward the backedge 822 thereof in the element height direction. Stated another way,the thickness, t_(1(osc)), of the region of the oscillation device 802near the MFS may be less than the thickness, t_(2(osc)), of the regionof the oscillation device 802 near the back edge 822 thereof.

It is of note that conventional MAMR heads do not include a magneticcapping layer (such as those disclosed herein) above the oscillationdevice 802. As such, process variations associated with the cleaningprocess lead to an undesirable, non-uniform thickness of the oscillatingdevice (and thus the trailing gap). For example, as noted above, afterremoval of the mask 820 and prior to the cleaning process, a thick SHinsulation layer 824 may be present behind the oscillation device 802 inthe element height direction. This thick SH insulation layer 824 mayfunction effectively as a milling mask, thereby making cleaning of theinsulation layer and the surrounding vicinity difficult. Without theprotection of the magnetic capping layer disclosed herein, there is arisk of over-cleaning the areas near the thick SH insulation layer 824,areas which include the oscillation device 802. Accordingly, without theprotection of such a magnetic capping layer, the cleaning process causesthe oscillation device 802 to ultimately have a non-uniform thickness inthe element height direction, as seen in FIG. 8F. Such conventionalmanufacturing techniques of MAMR heads may thus result in an undesiredvariation in the thicknesses of their respective oscillation devices(and the trailing gaps), leading to inconsistent reading/writingperformance of said MAMR heads.

As shown in FIG. 8G, a trailing shield 830 is deposited above theoscillation device 802 and the SH insulation layer 824. While not shownin FIG. 8G, a trailing shield seed layer may be positioned between atleast the oscillation device 802 and the trailing shield 830.

It is also important to note that while not shown in FIGS. 8A-8G, theprior art method may include additional steps, e.g., to define the widthof the oscillation device 802 in the cross track direction, to deposit atrack width (TW) insulation layer on either side of the oscillationdevice 802 in the cross track direction, etc.

It should be noted that methodology presented herein for at least someof the various embodiments may be implemented, in whole or in part, incomputer hardware, software, by hand, using specialty equipment, etc.and combinations thereof.

Moreover, any of the structures and/or steps may be implemented usingknown materials and/or techniques, as would become apparent to oneskilled in the art upon reading the present specification.

The inventive concepts disclosed herein have been presented by way ofexample to illustrate the myriad features thereof in a plurality ofillustrative scenarios, embodiments, and/or implementations. It shouldbe appreciated that the concepts generally disclosed are to beconsidered as modular, and may be implemented in any combination,permutation, or synthesis thereof. In addition, any modification,alteration, or equivalent of the presently disclosed features,functions, and concepts that would be appreciated by a person havingordinary skill in the art upon reading the instant descriptions shouldalso be considered within the scope of this disclosure.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

What is claimed is:
 1. A magnetic recording head, comprising: a mainpole configured to generate a magnetic field for recording data on amagnetic recording medium; an oscillation device positioned above themain pole in a track direction, the oscillation device being configuredto generate a high-frequency magnetic field; a magnetic capping layerpositioned above the oscillation device in the track direction, themagnetic capping layer having a front region at a media facing side(MFS) of the magnetic recording head and a rear region positioned behindthe front region in an element height direction, wherein a thickness ofthe front region of the magnetic capping layer is less than a thicknessof the rear region thereof, wherein at least a portion of an uppersurface of the magnetic capping layer is angled at a first angle ofinclination greater than 0° and less than 90° relative to a plane ofdeposition of the magnetic recording head, wherein a lower surface ofthe magnetic capping layer is angled at a second angle of inclinationgreater than 0° and less than 90° relative to the plane of deposition ofthe magnetic recording head, the second angle of inclination being lessthan the first angle of inclination; and a trailing shield positionedabove the magnetic capping layer in the track direction.
 2. The magneticrecording head as recited in claim 1, wherein a thickness of the frontregion of the magnetic capping layer is in a range from about 4 nm toless than about 25 nm.
 3. The magnetic recording head as recited inclaim 1, wherein a thickness of the rear region of the magnetic cappinglayer is in a range from greater than about 4 nm to about 25 nm.
 4. Themagnetic recording head as recited in claim 1, wherein the magneticcapping layer comprises one or more magnetic materials.
 5. The magneticrecording head as recited in claim 1, wherein the magnetic capping layercomprises at least one magnetic material in common with trailing shield.6. The magnetic recording head as recited in claim 1, wherein themagnetic capping layer comprises at least one of: Ni, Fe, and Co.
 7. Themagnetic recording head as recited in claim 1, further comprising atrailing shield seed layer positioned between the trailing shield andthe magnetic capping layer.
 8. The magnetic recording head as recited inclaim 7, wherein the trailing shield comprises an electricallyconductive non-magnetic material.
 9. The magnetic recording head asrecited in claim 1, wherein the upper surface of the magnetic cappinglayer lies substantially along a plane that inclines along the elementheight direction from the MFS at the first angle of inclination.
 10. Themagnetic recording head as recited in claim 1, wherein the oscillationdevice comprises a spin torque oscillator.
 11. The magnetic recordinghead as recited in claim 1, wherein the oscillation device has a uniformthickness in the element height direction.
 12. The magnetic recordinghead as recited in claim 1, further comprising an insulating layer,portions of which are positioned behind the oscillation device and themagnetic capping layer in the element height direction.
 13. The magneticrecording head as recited in claim 12, wherein the insulating layercomprises alumina.
 14. The magnetic recording head as recited in claim12, wherein an upper surface of at least a portion of the insulatinglayer positioned directly behind a back edge of the oscillation deviceand a back edge of the magnetic capping layer in the element heightdirection is angled at a third angle of inclination greater than greaterthan 0° and less than 90° relative to the plane of deposition of themagnetic recording head, wherein the third angle of inclination is equalto or greater than the first angle of inclination.
 15. A magnetic datastorage system, comprising: at least one magnetic recording head asrecited in claim 1; a magnetic medium; a drive mechanism for passing themagnetic medium over the at least one magnetic recording head; and acontroller electrically coupled to the at least one magnetic recordinghead for controlling operation of the at least one magnetic recordinghead.
 16. A method for forming a magnetic recording head, comprising:forming a main pole configured to generate a magnetic field forrecording data on a magnetic recording medium; forming an oscillationdevice above the main pole in a track direction; forming a magneticcapping layer above the oscillation device in the track direction,wherein the magnetic capping layer is configured to preserve a thicknessof the oscillation device; defining a stripe height of the oscillationdevice and a stipe height of the magnetic capping layer; depositing aninsulation layer behind the oscillation device and the magnetic cappinglayer in an element height direction; and cleaning an upper surface ofthe magnetic capping layer and an upper surface of the insulation layer,wherein after the cleaning: a thickness of a front region of themagnetic capping layer is less than a thickness of a rear regionthereof, the front region being positioned at a media facing side (MFS)of the magnetic recording head and the rear region being positionedbehind the front region in the element height direction; at least aportion of an upper surface of the magnetic capping layer is angled at afirst angle of inclination greater than 0° and less than 90° relative toa plane of deposition of the magnetic recording head; and a lowersurface of the magnetic capping layer is angled at a second angle ofinclination greater than 0° and less than 90° relative to the plane ofdeposition of the magnetic recording head, wherein the second angle ofinclination is less than the first angle of inclination.
 17. The methodas recited in claim 16, wherein after the cleaning, the oscillationdevice has a uniform thickness in the element height direction.
 18. Themethod as recited in claim 16, wherein the oscillation device comprise aspin torque oscillator.
 19. The method as recited in claim 16, whereinthe magnetic capping layer comprises at least one of: Ni, Fe, and Co.20. The method as recited in claim 16, further comprising depositing atrailing shield above the magnetic capping layer and the insulationlayer in the track direction.